The present invention relates to a stamp apparatus using a printing sheet.
As disclosed by Japanese Laid-Open Patent Application No. 7-251558, there is known a stamp apparatus using a porous printing sheet in which ink can be impregnated. A pattern is formed on a surface of the printing sheet, including a print portion which allows the permeation of ink and a non-print portion which block the permeation of ink. That is, ink is permeated through the printing sheet according to the pattern. The printing sheet is provided to the bottom of a body of the stamp apparatus. In order to repeatedly use the stamp apparatus without feeding ink thereto, the stamp apparatus is provided with an ink pad in which the ink is impregnated, the ink pad being interposed between the body and the printing sheet. When a user grips the body and urges the printing apparatus onto the medium so that the printing sheet is urged onto the medium, ink impregnated in the ink pad is transmitted through the printing sheet and transferred onto the medium.
However, such a stamp apparatus has a disadvantage such that the ink pad must be replaced (together with the printing sheet) when the ink impregnated therein has been used up. Such replacement increases the running cost of the stamp apparatus.
Another proposed stamp apparatus has an ink supply port (instead of the ink pad) provided in the body, through which ink can be fed to the printing sheet.
However, there is a tendency that the amount of ink fed to the location (on the printing sheet) far from the ink supply port is smaller than the amount of ink fed to the location close to the ink supply port. Accordingly, ink is not uniformly fed over an entire surface of the printing sheet, which causes a deviation of the ink density of the pattern printed on the medium.